SEMICONDUCTOR DEVICES AND DATA STORAGE SYSTEMS INCLUDING THE SAME

A semiconductor device includes a substrate; a stack structure on the substrate and including an alternating stack of interlayer insulating layers and gate electrodes; first and second separation regions each extending through the stack structure and extending in a first direction; a first upper separation region between the first and second separation regions and extending through a portion of the stack structure; a plurality of channel structures between the first and second separation regions and extending through the stack structure; and a plurality of first vertical structures each extending through a particular one of the first and second separation regions. Each of the first and second separation regions has a first width in a second direction that is perpendicular to the first direction. Each first vertical structure has a second width in the second direction, the second width being greater than the first width.